Manufacture of yarns or threads



Sept. 14, 1937. w CK r AL 2,092,800

MANUFACTURE OF YARNS OR THREADS Filed April 18, 1934 GEORGE C TYCEWLLIAM A- DSCKKE 1N IENTOKS A'TTO fIVE r5 Patented- Sept 14, 1931MANUFACTURE PATENT OFFICE 2.09am or m nus on 'rnncans William AlexanderDickie and George Crawford.

Tyce, Spondon, near Derby, England, alalgnon to .Celanese Corporation ofAmerica, a corporation of Delaware Q Application April .18, l9 4rserialNo. 721,118

' Ill Great Britain April 25, 1933 3 Claims.

' This invention relates to the manufacture of spun yarns 02'' threadsfrom artificial staple fibres.

Spun yarns may be produced either from natural staple fibre materialssuch as-wool or cot- 5 ton, or from continuous-filaments such as naturalsilk filaments or artificial filaments. In the latter case thecontinuous filaments may either be cut into staple lengths and then spunin the manner usual with natural staple fibres, or alternatively theymay be broken into staple lengths by passing them between pairs ofbreaking rollers rotating at difierent speeds, so as to draw out thefilaments beyond their breaking point. Methods of breaking continuousfilaments in this manner for the production of spun yarns are describedin U. S. application S. No. 696,375 filed 2nd November, 1933. Thestrength of spun yarns produced from continuous filaments in this manner-"-'depends upon the degree of twist which binds the fibres together,but in general is less than the strength of a continuous filament yarnof the same weight per unit length. It is one object. of the inventionto obtain a spun yarn whose strength is comparable to or even exceedsthe strength of '5 a yarn made from continuous filaments of likematerials and of like weight per unit length.

According to the present invention continuous filaments which have beenstretched beyond their elastic limit are converted into staple fibres,and

such staple fibres are spun into yarns. Stretched yarns which may mostsatisfactorily. be employed are those which have been stretched to ahigh degree, e. g. to 200, 300, or 500% or more of their former length.Such a high degree of stretching 88 may be efiected by treating theyarns during stretching with an agent adapted to assist the operation byreducing the elastic limit of the' ""material, as is described in U. 5.Patent No. 1,709,470 and U. S. applications S. Nos. 378,684

60 filed 16th July, 1929, 573,424 filed 6th November, 1931 and 602,844filed 2nd April, 1932. Suitable agents which may be employed with yarnsof cellulose acetate or other organic derivative of cellulose areacetone, ethylene methylene ether, I dioxane and similar cyclic ethers,and other agents referred to in the above specifications. A particularlyconvenient way of stretching .the yarns is to stretch them while theyare in the form of a warp, e. g. as described in U. S. applica- I0 tionS. No. 602,8 14.

Continuous filament yarns which have been stretchedbeyond their elasticlimit possess improved properties, and in particular a. greatlyincreased strength. In addition to the increased l6 strength, resultingfrom the stretching operation to which the filaments have beensubmitted, the

filaments are reduced in denier. When, therefore, such filaments areconverted into staple fibres and spun into a yarn, not only is theincreased strength of the filaments transmitted to the spun yarnproduced, butv also the greater fineness of the filaments in itself hasan effect of increasing the strength of the spun yarn produced and ofimparting generally improved properties bf evenness and finenessthereto.

Continuous artificial filament yarns employed for the purposes of thepresent invention may have been stretched beyond their elastic limit atany stage in their production, either during or after their formation byextrusion and hardening by coagulation or evaporation.

While the invention may be applied to continuous artificial filaments ofany type. e. g. to artificial silk of reconstituted cellulose, it isespecially advantageous in connection with continuous artificialfilaments of cellulose acetate or other organic derivatives ofcellulose. Examples of other organic derivatives of cellulose are othercellulose esters such as cellulose formate, propionate or butyrate andcellulose ethers such as ethyl and benzyl cellulose.

As mentioned above the continuous filaments may be converted into staplefibres by cutting bundles of continuous filaments in one or more stepsinto lengths equivalent to the length of staple fibre of wool or cotton,or into any other desired lengths. Alternatively the yarns may be brokeninto staple fibres by passing them through breaking rolls rotating atdiflerent peripheral speeds, the mass of staple fibres so producedemerging from the last pair of breaking rolls either being treated as aroving for subsequent the stretching or continuous filaments beyondtheir elastic limit also tends to reduce the extensibility, it mightappear that some disadvantages would accrue from the cumulativereduction obtained. This difiiculty may readily be overcome, however, bytreating the yarns in such a manner as to restore the extensibility toan extent which will enable them to be worked satisfactorily in textileoperations for which they are destined. Conditioning treatments withthis object in view are described in U. 8. application S. No. 696,184filed 1st November, 1933. While such a treatment to restore theextensibilitymay be applied to a stretched continuous filament yarnbefore it is broken into staple fibres, it is preferred that thetreatment should be postponed until after the formation of the spunyarn, so that loss in extensibility resulting from the breakingoperation may also be recovered. The treatment may however be appliedboth to the continuous filaments before breaking into staple fibres, andto spun yam after spinning.

By way of example one form of apparatus suitable for the production ofstaple fibre yarns according to the present invention will now bedescribed in greater detail with reference to the accompanying drawing,which illustrates the apparatus in side elevation.

In the drawing, stretched continuous filaments I are drawn from a supplybobbin 2 and through a guide 3 by means of feed rollers 4 which forwardthe filaments l to the first of two pairs of breaking rollers, 5, 6, 'I,8. The feed rollers 4 are rotated at a peripheral speed slightly higherthan that of the first pair of rollers 5, 5 so as to feed the filamentsl to the rollers 5, 5.

The second pair of rollers I, 8 are rotated with a higher peripheralspeed than the first pair of rollers 5, 6 so as to draw out and breakthe continuous filaments between the pairs of rollers, converting theminto a continuous staple fibre product.

In order that the filaments may be securely gripped by each pair ofrollers 5, 5, I, 8 the arrangement described in U. S. application S. No.714,552 filed March 8, 1934, corresponding to British application No.9311/33 filed 28th March, 1933 is adopted, so that,- despite theincreased strength of the filaments which encourages slipping of thefilaments through the breaking rollers, slipping may be substantiallyprevented. For this purpose, the lower rollers 5 and I are covered withprotuberances which localize the pressure applied between the rollers,while the upper rollers 6, 8 are covered with a jacket 9 of slightlyyielding material into which the protuberances of the lower rollers 5, Isink.

Between the pairs of rollers 5, 6 and I, 8 the filaments are guided andconfined by means oi a guide tube It which is traversed to and troiromend to end of the rollers l, 5, 6, I, 8 by means of a traverse bar I Ion which the tube III is mounted. The upper rollers 5, 8 are presseddown on the lower rollers '5, I by means of a bridge II which isspringor weight-loaded by,means of a rod l2. The continuous staple fibreproduct I3 emerged from the second pair 01' rollers I. 8 proceedsto theguide I of a ring spinning device l5 by means of which it is twistedinto a yarn and wound.

What we claim and desire to secure by Letters Patent is: I

1. Process for-the production of staple fibre yarns from continuousfilaments, said process comprising stretching continuous filamentsbeyond their elastic limit, subsequently subjecting such stretchedcontinuous filaments to a breaking operation to form a continuous staplefibre product, spinning such staple fibre product into a yarn, andsubmitting the spun yarn so produced to a conditioning operation torestore at least in part the extensibility of the fibres thereof.

2. Process for the production of staple fibre yarns from continuousfilaments containing an organic derivative of cellulose, said processcomprising stretching such continuous filaments beyond their elasticlimit, subsequently subjecting such stretched continuous filaments to abreaking operation to form a continuous staple fibre product, spinningsuch staple fibre product'into a yarn, and submitting the spun yarn soproduced to a conditioning operation to restore at least in part theextensibility of the fibres thereof.

3. Process for the production of staple fibre yarns from continuousfilaments containing cellulose acetate, said process comprisingstretching such continuous filaments beyond their elastic limit,subsequently subjecting such stretched continuous filaments to abreaking operation to form a continuous staple fibre product, spinningsuch staple fibre product into a yarn, and submitting the spun yarn soproduced to a conditioning operation to restore at least in part theextensibility of the fibres thereof.

. WILLIAM ALEXANDER DICKIE.

GEORGE CRAWFORD TYCE.

